Online investigations on ozonation products of pyrene and benz[a]anthracene particles with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer

The reaction products of ozone with pyrene and benz[a]anthracene absorbed on azelaic acid particles under the pseudo-first-order reaction conditions have been investigated with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The pyrene and benz[a]anthracene particles with the initial concentrations of similar to 1 mg m(-3) are respectively exposed to similar to 22 ppm ozone in a reaction chamber with a volume of similar to 180 L. The time-of-flight mass spectra of the particulate ozonides are obtained. The assignments of the mass spectra reveal that 4-carboxy-5-phenanthrene-carboxyaldehyde (71%) and hydroxypyrene (23%) are the main solid state ozonides of pyrene, while 2-(2-formyl)phenyl-3-naphthoic acid (35%), hydroxybenz[a]anthrone (30%), and benz[a]anthracene-7, 12-dione (18%) are the main solid state ozonides of benz[a]anthracene, The pathways of the ozonations are proposed in the paper. (C) 2009 Elsevier Ltd. All rights reserved.